The present invention relates generally to the field of displays. The present invention more specifically relates to the field of interactive displays such as touch screens and touch panels.
It is known to provide for interactive displays such as touch screens and touch panels for use with devices (such as computers, handheld devices, personal digital assistants (PDAs), information kiosks, and the like).
Touch screens allow for interaction (such as user interaction or user interface) with the device via the display. A user may interface with the device or with software via the display, by touching the display in certain areas, inputting text or graphic characters into the device, etc. One such interface may be a Graffiti™ writing section, or other hand recognition software, for tracing alpha numeric characters as input.
Touch screens typically include three layers: a touch panel layer, a display layer below the touch panel layer, and a backlight layer below the display layer. The touch panel layer is the layer that is receptive to motion, touch, position, etc. of objects such as a stylus, pen, pointing device, a human's finger, etc. Typical touch panels may use resistive or capacitive touch panels to provide an interactive display.
Resistive touch panels typically consist of a glass or acrylic panel that is coated with electrically conductive and resistive layers. When operating, an electrical current moves through the touch panel. When pressure is applied to the touch panel, the layers are pressed together, causing a change in the resistance and a touch event is detected.
A capacitive touch screen consists of a glass panel with a capacitive (charge storing) material coating its surface. Sensors located at corners of the screen typically measure the capacitance of an object touching the coated surface. X and Y coordinates of any touch event are then determined based on the relative capacitance measurements made by the four sensors.
These touch panel layers are typically constructed from glass or acrylic. The touch panel layer typically may have a thickness of approximately 2 millimeters. The inclusion of the touch panel layer to the device adds to the overall size (such as thickness) of the device, as well as adding to the weight of the device. As devices such as PDAs become smaller and lighter, there is a need to reduce both the size and weight of the devices. Accordingly, it would be advantageous to provide an interactive display for use with a device, such as a PDA, which would not require a touch panel layer.
Additionally, the touch panel layer may have a transparency of 80-85 percent. That is, light passing through the touch panel will have 80-85 percent of its original brightness or intensity. Due to the touch panel layer, the brightness or intensity of the display layer is diminished. In order to have a certain level of brightness or intensity, the display layer must have a higher output to overcome the losses in the touch panel layer. This in turn places a greater burden or drain on a power source (typically batteries).
Accordingly, it would be desirable to provide an interactive display that would not cause a reduction in the intensity or brightness of the display layer. It would further be advantageous to provide an interactive display that would provide for the level of brightness or intensity of present displays, while also requiring less power than typical displays. It would further be advantageous to provide a display (such as a touch screen) which would provide for user input or interface via the display. The techniques below extend to those embodiments which fall within the scope of the appended claims, regardless of whether they provide one or more of the above-mentioned advantageous features.